Internal combustion engine



INTERNAL GOMBUS TION ENGINE Filed April 3, 1935 2 Sheets-Sheet 1Jizven'l'or March 2, 1937. v. P. HELMING 2,072,474

INTERNAL COMBUSTION ENGINE Filed April 3, 1935 2 sheets-sheet 2 PatentedMar. 2, 1937 UNITED STATES PATENT OFFICE INTERNAL COMBUSTION ENGINEVernon P. Helming, Amherst, Mass. Application April 3, 1935, Serial No.14,431

2 Claims.

The present invention relates to internal combustion engines, and moreparticularly to a rotary valve for internal combustion engines employingspark plugs to ignite an explosive mixture. The object of the presentinvention is to provide a novel and improved automatic timingarrangement for use with internal combustion engines.

With this and other objects in view, the present invention contemplatesthe provision in an internal combustion engine of novel and improvedmeans for automatically changing the timing of the engine.

This and other features of the present invention will be clearlyunderstood from the followingdescription taken in connection with theaccompanying drawings in which Fig. 1 is a view in vertical section of aportion of an engine embodying the invention; and Fig. 2 is a plan view,partly in section, of the engine.

The engine illustrated includes a cylinder block 2 bored to form acylinder 4 in which is mounted for reciprocation a piston 6. Attached tothe cylinder block 2 by means of bolts 8 is secured a cylinder head I0having a water jacket l2 surrounding the walls thereof. The water jacketalso extends downwardly through interconnecting passages (not shown)into the cylinder block 2.

Engines provided with rotary valves have heretofore been constructedwith curved or dome shaped end walls to avoid possible lines of leakagewhich might form along corners formed by intersecting surfaces of thecylinder and end Wall. Now while the curvature of a dome shaped cylinderhead assists in preventing distortion of a closely fitting valve underextremes of temperature, it is also true that where the surfaces arecurved or dome-shaped, special forming tools are required. In allrespects, the manufacture of accurate curved surfaces is more difficultthan of flat surfaces. Other rotary-valve constructions include variousarrangements of intake, exhaust, and spark plug passages formed both inthe end and side walls of the cylinder so as to permit as great adistance as possible between the entrances of the various passages. Withdifferently spaced passages a plurality of openings is required in therotary valve, so that a corresponding increase in the liability ofleakage exists.

The intake, exhaust, and spark plug passages, of the present engine, areall grouped closely together to pass through a single easily machinedflat surface 14 at the end of the cylinder having a disk-shaped valve l6closely engaging it. To prevent leakage between the surface of the valveI6 and the surface I4 of the cylinder-head endwall, the valve [6 isformed with an imperforate cylindrical skirt l8 conforming closely withthe side wall of the cylinder head. With this arrangement, the heatedgases must make their way between the cylindrical skirt and the sidewall and through a restricted space of considerable length in order toescape from compres sion. The corner formed between the end wall surface14 and the side wall of the cylinder is not subject to such highpressure as it would be without the presence of the skirt portion 18 ofthe valve; and since the skirt may be formed of relatively thinmaterial, there is a tendency of the valve under high temperature andpressure to expand slightly in the direction of the cylinder side wall,thereby decreasing the possibility of leakage. The valve is alsoprovided with a single opening 20 which may be brought into successiveregistration with the intake passage indicated at 22, the exhaustpassage indicated at 24, and the spark-plug passage indicated at 26,entering the end wall of the cylinder. With a single opening 20 there isless likelihood of leakage than there would be with a series ofopenings, and the maximum pressure which occurs during the power strokeof the engine assists y in holding the disk shaped valve portion 16against the end wall surface 14. The explosive stroke occurs, of course,while the spark plug passage 26 is exposed, but no leakage is permittedfrom passage 26 on account of its being closed by a plug 28.

To strengthen the valve and reduce the possibility of undesirabledistortion from heat, there are provided between the disk-shaped portionl6 of the valve and the skirt portion l8 a series of ribs 30. The ribsalso assist in distributing the cooling effects of the water jacket 12in the cylinder head from the skirt portion I 8 over the disk portion itof the valve.

The valve is formed at the lower end of a vertical shaft 32 extendingdownwardly through the end wall of the cylinder head, and the valve isyieldingly forced against the end wall surface M by a spring 34 coiledaround the shaft and compressed between the top of the cylinder head anda collar 36 around the shaft. The collar 36 forms the lower member of athrust bearing h-aving an upper member 38; and above the bearing 38there is secured to the shaft a gear 40 held in place by a pair of locknuts 42.

To rotate the valve supporting shaft 36 the valve gear 4|] meshes with aworm 44 fixed to a lay shaft 46 horizontally arranged and rotatablymounted in bearings 48 at the top of the cylinder head. The lay shaftalso carries a worm 50 meshing with a gear 52 on a shaft 54- on which ismounted rotating parts of a spark distributor or timer 56, thearrangement being such that the valve and timer are operated in unison.

To adjust automatically the timing of the engine, according to thepresent invention the lay shaft 46 is mounted for lengthwise movement inthe bearings 48 and is provided with a piston 58 rotatably mounted atits forward end. The shaft 46 carries an enlarged flange 60 actingthrough a thrust bearing 62 against the plunger 58 and also through asecond thrust bearing 64 on a flanged collar 66 enclosing a coiledspring 68. The coiled spring 68 is compressed between the collar 66 andone end of a cylinder 10 surrounding the piston 58 and having a suitablemounting on the cylinder head In. The cylinder '10 is closed at itsforward end by a cover plate 12 having a threaded opening 14 connectedto the usual pressure lubricating system of the engine. As the speed ofthe engine increases, the pressure of the oil is increasedcorrespondingly, so that the piston 58 is forced rearwardly in thecylinder l0 and the shaft 46 moved lengthwise. This movement causes asimultaneous advance in the timing of the valve [6 and the spark timer56.

To lubricate the valve operating mechanism the main shaft 46 iscentrally drilled at T6, and the forward end of the shaft is formed witha reduced tubular portion 18 extending through a packing gland in thepiston 58. The central passage 16 of the shaft 46 is connected byoutlets 8I to the bearings 48 and also by an outlet 82 extending throughthe side of the worm 44. The outlet 82 is normally closed at its outerend by a. spring-pressed ball 83 projecting slightly above the surfaceof the gear 44 in such position that it will be engaged by the gear 48as the engine operates. During the short engagement with the ball 83 ineach rotation of the shaft 46, oil will be ejected under pressure to thegears 40 and 44. Any excess oil will drop by gravity into afunnel-shaped portion 84 on the cylinder head and thence downwardlyalong a groove 86 in the bearing of the valve shaft 32 to the uppersurface of the valve l6. As a result of the cooling effects of the waterjacket about both end and side walls of the cylinder head on the valvedisk l6 and its skirt l8, the oil is permitted to remain on the valveand lubricates it properly.

As a further means of increasing the efiiciency of the valve, the teethon the gear 40 are cut in an irregular fashion, the spacing of the teethat the upper side of the gear being unequal so that when the worm 46 isrotated, it will cause a rapid opening or closing of the valve; whilethe time in which the valve remains open or closed will be relativelyincreased. By this construction it is possible to permit a slight dwellin the movement of the valve during the instant of extreme pressure asthe explosive charge is fired within the cylinder. I

While the invention is described in connection with a single cylinder,it is particularly adapted for use with an engine having a plurality ofcylinders. In this case the main horizontal shaft 46 extends across thetops of all the cylinders, there being but a single timer which isadjusted simultaneously with the automatic timing of the valves in allthe cylinders.

Having thus described an embodiment of the invention, what is claimedis:

1. An internal combustion engine having, in combination, a cylinder, apiston in the cylinder, a spark timer, a timer shaft, a lay shaftarranged transversely of the timer shaft and provided with a passage tolubricate the lay shaft, gears on said shafts for driving the timershaft from the lay shaft, a piston at the end of the lay shaft, and acylinder for the piston on the lay shaft carrying oil under a variablepressure depending upon engine speed for shifting the lay shaftlengthwise automatically to change the timing of the spark timer.

2. An internal combustion engine having, in combination, a cylinder, apiston in the cylinder, a rotary valve in the cylinder, avalve-supporting shaft extending through the cylinder wall, a gearcarried by the shaft externally of the cylinder, a spark timer, a timershaft, a gear on the timer shaft, a lay shaft arranged transversely ofthe valve supporting and timer shafts, gears on the lay shaft forrotating the valve and timer, a piston at the end of the lay shaft, anda cylinder for the piston on the lay shaft carrying oil under variablepressure depending upon engine speed for shifting the lay shaftlengthwise automatically to change the timing of the valve and sparktimer.

VERNON P. HELMING.

